1. Field of the Invention
The present invention relates generally to a satellite antenna or a satellite dish. More particularly, the invention relates to an antenna for receiving satellite broadcast, which provides easy and convenient installation.
2. Description of the Related Art
In order to receive a satellite broadcast program, the orientation of the satellite dish has to be adjusted for directing to a satellite accurately. Upon adjustment, since the radio wave from a broadcasting satellite (BS) is strong, sufficient signal intensity can be obtained even with a certain error in orientation. However, since the radio wave from a communication satellite (CS) is weak, it becomes impossible to obtain sufficient signal intensity unless the orientation of the antenna is correctly directed to the satellite. Various methods and systems for solving such problem have been developed and proposed. The conventional methods and systems are mainly based on the following two systems.
The first system adopts a method to adjust the orientation of the antenna by means of a compass and a level. The second system adopts a method for capturing a direction at which the intensity of received signal becomes at its available maximum.
The first system, namely the system employing the compass and the level, is characterized in simplicity. However, the north directed by the compass deviates about 6.5 degrees from the north of the earth's axis, which causes it difficult to adjust the orientation accurately within one degree of deviation. Furthermore, since the compass is influenced by environmental magnetic field, correct direction cannot be indicated if an antenna mount or a handrail of veranda are formed of magnetic body or the antenna is placed close to a domestic power source or a power cable. Particularly, in case of the antenna of the type, to which a direct current is supplied to a converter module, since a direct current magnetic field is generated quite close to the antenna and a compass, the influence of the magnetic field is significant. Due to the foregoing problems, the method employing the compass can not always enable us to adjust the satellite antenna orientation accurately.
The second system, namely the system employing signal intensity received by a satellite antenna, concerns the adjustment after the satellite antenna has caught the radio wave from the satellite. In case of the CS broadcasting, in which the radio wave is weak on the ground, difficulty is encountered in initially capturing the radio wave. Also, the orientation of the antenna often deviates from the direction with maximum reception intensity during the antenna fixation because fastening the antenna mounts on a mount pole changes the antenna direction somewhat. In the method employing the intensity of the received radio wave, difficulty is encountered to make judgment how much the orientation deviates and to keep the orientation during the fixation of the antenna.